O'Connor was arrested last month after authorities were alerted to his possible plans for an attack on ACES High School.

According to court documents, O'Connor wrote in his journal about ordering a gun that matched a weapon used in the 1999 attack at Columbine High School. He reportedly planed his attack to coincide with its anniversary.

Public defender Rachel Forde requested the judge to delay the Monday arraignment, citing concerns about O'Connor's ability to get a fair trial.

The judge denied the request. O'Connor remains in jail on a $5 million bond.